AnswerHello Frankie,
This depends on what the initial complaint is. You see, one is used as part of the defrost system to tell the main control the temperature of the evaporator coils, and the other is used as a communication device to tell the main control the temperature of the freezer compartment. If you're not sure, you can replace both. Be sure when you replace a sensor, to use a small amount of white lube to seal the electrical connection from moisture so the connectin won't corrode and lose connection causing a food loss.